Nanobiotechnology has emerged as an important branch of nanotechnology with biological or biochemical applications and activities at nano level in order to design or to study existing properties of nature. The biosynthetic utilization, especially fungi, has emerged as a novel method for the synthesis of metal nanoparticles. The metal nanoparticles are considered as fundamental molecular building blocks for nanotechnology. In the present study, Aspergillus niger was utilised for the extracellular synthesis of biogenic silver nanoparticles (AgNPs). The fungus mycelium is exposed to the 1mM silver nitrate solution that prompts the fungus to produce enzymes and metabolites for its own survival and reduces Ag+ ions into Ag0 due to catalytic effect of the fungal enzymes and metabolites. The primary confirmation of AgNPs synthesis was confirmed by the colour change from whitish colour to yellowish brown colour, which was confirmed through absorption UV-Visible spectrophotometer. The Fourier transform infrared spectroscopy analysis confirmed the quantitative analyses different reaction products revealed capping of silver nanoparticles. Field emission scanning electron microscopy (FESEM), Atomic force microscopy (AFM) analysis indicates that extracellular AgNPs are having average roughness and are in average size of 25-65nm. FESEM analysis showed AgNPs are spherical shaped and monodispersed. The biological Silver nanoparticles are known to have bactericidal effects against MDR strains of S. auras, B. cereus, E. coli, V. cholera and P. vulgaris. Resistance of bacterial infections has emerged in recent years has became major health problem. The bactericidal activity of biologically synthesised AgNPs was carried against pathogenic MDR strains in combination with commercial antibiotics which showed enhanced efficacy antibiotics against selected pathogens. Thus, the present study demonstrates that AgNPs in combination with antibiotics are showing potential bactericidal property could be used as powerful weapons against the MDR pathogens.
